The present invention relates to a digital communication method, and, more particularly, to a digital communication method operative to provide each node of a pair of nodes of a digital communication system, such as an InfiniBand fabric, with sufficient information about the other node of the pair to facilitate the setting of parameters of that node so as to facilitate substantially optimized communication between the two nodes.
The present invention addresses the problem of automatically connecting nodes, such as those of an InfiniBand fabric, with each other so as to take advantage of the capabilities of each node as much as possible in view of the limitations of the nodes and their environment. In particular, it is desirable to make use of Double Data Rate (DDR) transmission if both nodes are capable of such, and otherwise use Single Data Rate (SDR) transmission. Additionally, it is desirable to assess the quality of the communication link for a variety of combinations of transmission and reception parameters for each direction of communication, and then select the best such combination for each direction for the transmission of user data.
Active Cable is a transmission medium that behaves differently from ordinary copper cabling. Although transmission and reception parameter settings appropriate for Active Cable can be used for copper cabling, and vice versa, this leads to a subtle degradation of performance. The present invention provides the ability to automatically distinguish Active Cable from copper cable.
There is thus a widely recognized need for, and it would be highly advantageous to have, a method of digital communication that automatically selects DDR, if possible, and otherwise selects SDR, and also automatically selects substantially optimal transmission and reception parameters for each direction of data transmission.